1. Field of the Invention
This invention relates to a thermal transfer recording apparatus, which is used in a manner having detachably mounted a so-called refill type ink film cassette wherein the ink film is replaced or refilled with a new supply, and the refill type ink film cassette, and an ink film reel, which is used in the refill type ink film cassette.
2. Description of the Related Art
The thermal transfer recording apparatus is provided with a platen roller and a thermal head, which is freely pressed against and separated from the platen roller. A recording paper is conveyed through the contacting surface between the platen roller and the thermal head. An ink film, which has an ink with thermally fusible or sublimating properties applied to one surface, is conveyed into the contacting surface between the recording paper and the thermal head. This ink film is drawn out from a reel on the supply side and wound on a reel on the take-up side. When a color image is reproduced by one thermal head on the recording paper, the thermal transfer recording apparatus uses the ink film which has the inks in the colors of yellow, magenta, and cyan applied sequentially in the order on the surface of a thin film base.
The ink film is drawn out from the supply reel and conveyed in conjunction with the motion of the recording paper by friction force between the ink film and the recording paper, which is conveyed between the platen roller and the thermal head in a state of being pressed against the platen roller, during the printing process. The ink film paid out of the supply reel is wound on the take-up reel by rotating the take-up reel with a motor installed in the main body of the thermal transfer recording apparatus.
In recent years, an ink film cassette, which holds a supply reel and a take-up reel and is freely attached to and detached from the main body, is applied to the thermal transfer recording apparatus for improving the efficiency of the setting work of the ink film.
The ink film cassette of a disposable type has been proposed, for example, in consideration of the convenience of use. In this case, the cassette is a consumable good and thus wholly replaced with a newly supplied cassette when the built-in ink film is used up.
From the viewpoint of the global ecology, there has been found growing recognition that an ink film cassette of the so-called refill type with ink film which is replaced or refilled, is desirably used in the place of the disposable cassette.
The refill type cassettes of this class are known in the following various types. In one type of the refill type cassette, a user identifies a type of an ink film and sets the ink film in a cassette corresponding to the type of the ink film. In the thermal transfer recording apparatus that uses this type of ink film cassette, the attachment of the cassette is checked and a type of the ink film is identified by detecting the attached cassette.
The conventional refill type ink film cassette indeed is at an advantage in affording due consideration for the environment. It has the problem, however, that the apparatus is incapable of discerning between the presence and the absence of the film until it starts a printing operation even though a user, while replacing a spent ink film with a new supply, happens to forget to place an ink film in the cassette and set this cassette in the apparatus.
Further, this ink film cassette compels a user to incur the trouble of ensuring coincidence between a type of the ink film and a type of the cassette in case of the replacement of the ink film. It has still another problem that the ink film cassette must be manufactured or owned exclusively for the ink film of the particular type. If the user fails to secure the coincidence between the ink film and the cassette, the thermal transfer recording apparatus cannot detect the failure and the ink film or the recording paper wastefully consumed.
JP-A-05-162,405 discloses a cassette of the disposable type, which is so designed as to identify the type of the ink film. This cassette has a ring with a mark indicative of the type of ink film, which is rotatably disposed at one end of a reel for winding an ink film. It attains identification of the type of the ink film by causing the ring to rotate. Namely, this cassette can acquire the information on the film by only rotating the ring without requiring rotating the reel. However, it inevitably complicates the mechanism for rotational drive because the cassette must exclusively rotate the ring. If this method is applied to the refill type cassette, it requires that a user mounts the ring to the reel or a reel with a built-in ring is manufactured. The attempt results in complicating the work of replacement and increasing the cost.
The conventional thermal transfer recording apparatus is provided in the main body with a supply side torque limiter, which is connected to the supply reel and gives a braking force to the supply reel after the ink film cassette has been set in place. This supply side torque limiter continues to give a braking force to the supply reel while the ink film is being paid out of the supply reel. As a consequence, the limiter fulfills the purpose of transmitting due tension to the ink film and preventing the ink film from forming wrinkles during the printing process.
Further, a take-up side torque limiter, which limits a driving torque of the take-up reel, is disposed between the take-up reel and the motor in the main body of the thermal transfer recording apparatus. This take-up side torque limiter is provided for the following reason besides the reason of transmitting due tension to the ink film during the printing process. The conveying speed of the recording paper and the ink film must be equalized in the printing unit. However, the winding speed of the ink film on the take-up reel is inevitably varied as the roll diameter of the ink film wound in the take-up reel varies even when the supporting shaft of the take-up reel is rotated at a fixed speed. It is, therefore, provided with the take-up side torque limiter for enabling the winding speed to follow the conveying speed of the ink film in the printing unit and winding the ink film without slacking on the take-up reel.
The provision of the supply side and the take-up side torque limiters inside the thermal transfer recording apparatus complicates the arrangement of the recording apparatus, and boosts the cost, and inhibits all efforts to miniaturize the apparatus. The torque limiters provided inside the apparatus are required to possess durability on a par with other components used inside the apparatus, for example the durability to permit normal formation of images on 60,000 recording papers. Namely, the torque limiters must be relatively expensive. And, the use of these torque limiters inevitably results in adding to the cost of the thermal transfer recording apparatus as a whole. The present inventors have proposed an ink film cassette with a built-in supply side torque limiter and a take-up side torque limiter for the purpose of simplifying the main body of a thermal transfer recording apparatus and lowering the cost (JP-A-07-329,385). This ink film cassette is so designed that a user can refill an ink film by a simple procedure. And, the number of disposable components is decreased to the fullest possible extent and due respect is paid to the problem of environment.
The ink film cassette with built-in torque limiters enjoys the above advantage. However, the cassette incurs the possibility that a user forgets the torque limiters, or mistakes the supply side torque limiter for the take-up side torque limiter or vice versa and misplaces the torque limiters, in case of the work of refilling an ink film.
An object of this invention is to provide a thermal transfer recording apparatus, which is capable of simply and easily discerning between the absence and presence of an ink film prior to the start of the printing operation.
A further object of this invention is to provide a thermal transfer recording apparatus, which is capable of simply and easily identifying a type of the ink film and discerning erroneous mounting of the ink film prior to the start of the printing operation.
Another object of this invention is to provide a refill type ink film cassette and an ink film reel used for the cassette.
Still another object of this invention is to provide an ink film cassette, which is applicable to a plurality of types of ink films and is capable of identification of the type of the ink film.
Yet another object of this invention is to provide an ink film cassette, which ensures inexpensive prevention of the misplacement of torque limiters, precludes erroneous attachment of the torque limiters, and avoids enlarging the cassette without sacrificing the facility of both attachment and detachment of reels.
A further object of this invention is to provide an ink film cassette, which ensures inexpensive prevention of the misplacement of torque limiters and precludes not only the torque limiters but also reels from being erroneously attached without sacrificing the facility of both attachment and detachment of reels.
One aspect of the present invention concerns a thermal transfer recording apparatus with a detachably mounted ink film cassette having an ink film for transferring an ink applied to the ink film to a recording paper by a heating element: and forming an image on the recording paper, which comprises the ink film cassette which holds a supply reel that has the ink film wound around a shaft, and a take-up reel that takes up the ink film wound around the shaft of the supply reel on a shaft; detecting units which detect the reels mounted in the ink film cassette; and a control unit which discerns between a presence and an absence of the ink film based on a signal outputted from the detecting units. In this thermal transfer recording apparatus, the detecting units detect the reels and the controller discerns the presence of the ink film when the ink film cassette with the reels is mounted in the apparatus. Accordingly, the presence or the absence of the ink film wound on the reels is detected and the possible missing of the ink film can be simply and easily checked prior to the start of the printing operation. Then, a alarm to the user maybe outputted or a printing action may be done, depending on the outcome discerned by the controller concerning the presence and the absence of an ink film.
A further aspect of this invention concerns a thermal transfer recording apparatus with a detachably mounted ink film cassette having an ink film for transferring an ink applied to the ink film to a recording paper by a heating element: and forming an image on the recording paper, which comprises the ink film cassette holding a supply reel, which has the ink film wound around a shaft, and a take-up reel, which takes up the ink film wound around the shaft of the supply reel on a shaft; targets for detection, which are provided at edges of the reels held in the ink film cassette; detecting units which detect the targets; and a control unit which discerns between a presence and an absence of the ink film based on a signal outputted from the detecting units. In this thermal transfer recording apparatus, the detecting units detect the targets at the edges of the reels and the controller discerns between the presence and the absence of the ink film when the ink film cassette with the reels is mounted in the apparatus. As a result, the possible missing of the ink film can be simply and easily checked prior to the start of the printing operation.
Another aspect of this invention concerns an ink film detachably mounted in a thermal transfer recording apparatus and having an ink film coated with an ink, which comprises a supply reel. which is wound with the ink film; a take-up reel which takes up the ink film paid out of the supply reel; and a mark which is placed at an edge of either of the reels and indicates a type of the held ink film. The mark is preferably disposed in the edge of the supply reel. Concerning this ink film cassette, the mark indicates a type of the ink film. A type of the ink film and the erroneous mounting of the ink film can be simply and easily discerned prior to the printing operation by merely mounting the ink film cassette in the thermal transfer recording apparatus.
Still another aspect of this invention concerns an ink film reel being wound with a ink film for a thermal transfer recording apparatus for transferring an ink applied to the ink film to a recording paper by means of a heating element, and forming an image on the recording paper, which comprises a target for detection which is provided in at least either of opposite edges of the reel, and corresponds to a specific type of the ink film. It is preferable that the ink film reel is detachably mounted in the ink film cassette, and further the ink film reel held in the ink film cassette is detachably mounted in the thermal transfer recording apparatus. According to this arrangement, a type of the ink film can be discerned based on the target that is disposed in the ink film reel and not based on such factors as the shape of the ink film cassette. It does not require manufacturing or owning an ink film cassette used exclusively for one type of ink film. Namely, one type of the cassette can correspond to a plurality of types of ink films and permit perfect identification of such different types of ink films. And, the ink film reel proves to be advantageous for use in the refill type cassette in respect that a user is free from the trouble of deliberately causing the type of the cassette to coincide with the type of the ink film, in case of the replacement of the ink film.
Yet another aspect of this invention concerns an ink film cassette for being detachably mounted to a thermal transfer recording apparatus, which comprises a supply reel which is wound with an ink film; a take-up reel which takes up the ink film paid out of the supply reel; a braking unit which gives a braking force to the supply reel in the cassette; a first frame which holds the supply reel and the take-up reel; and a second frame which holds the braking unit and is detachably mounted in the first frame. In the arrangement of the ink film cassette, the replacement of a spent ink film is composed of removing the supply reel and the take-up reel from the first frame while keeping the braking unit supported on the second frame, and then setting a newly supplied reel in place. It essentially eliminates the possibility that the braking unit is missed or the braking unit is mistaken and is erroneously mounted on the take-up side during the replacement of the ink film. And, it is made possible to reuse and recover the braking unit, decrease the number of waste components to the fullest possible extent and contribute to the conservation of the environment. Incidentally, the first frame holds the supply reel and the second frame holds the braking unit separately. The attachment and detachment of the supply reel with respect to the first frame are attained without paying any respect to the braking unit and thus are accomplished with ease. Moreover, it does not require the space, which is used for the work of connecting the supply reel with the brake unit, and prevents the possible increase of the size of the cassette.
Another aspect of this invention concerns an ink film cassette with a built-in torque limiter for being detachably mounted in a thermal transfer recording apparatus, which comprises a first frame which holds a reel connected to the torque limiter; and a second frame which holds the torque limiter and is freely attached to and detached from the first frame; the reel and the torque limiter having ratchet shaped connected surfaces respectively. The arrangement of the ink film cassette essentially eliminates the possibility that the torque limiter is missed or the torque limiter is mistaken and erroneously mounted during the replacement of the ink film. And, it is made possible to reuse and recover the torque limiter. Incidentally, the first frame holds the reel and the second frame holds the torque limiter individually. The attachment and detachment of the reel with respect to the first frame can be attained without requiring attention to the torque limiter and can be fulfilled with ease. Moreover, it can save the space, which would be otherwise required for the work of connecting the reel with the torque limiter, and prevent the possible increase of the size of the cassette. In addition, the connected surfaces of the reel and the torque limiter are each formed in the shape of a ratchet. The inclined faces (resembling saw teeth) of the ratchets cause the reel and the torque limiter to be relatively rotated and be perfectly engaged with each other and brought into perfect union even in the absence of correct union of the two connected surfaces during the interconnection between the reel and the torque limiter. In brief, the reel does not need to be accurately positioned in mounting the reel. The replacement of the ink film is done with ease and the connection of the reel and the torque limiter is facilitated.
Another aspect of this invention concerns an ink film reel for use in an ink film cassette with a built-in torque limiter, which comprises a ratchet shaped surface that is provided in an edge and connected to the torque limiter. The ink film reel having the ratchet, shaped edge does not need to be positioned accurately in mounting. Accordingly, the reel is easily mounted to the ink film cassette with a built-in torque limiter and connected with the torque limiter as well.